NNWSI repository design approach

A designis being developed for a nuclear wasted repository at the Yucca Mountain site in Nevada. This design can be used to support the recommendation of that site for characterization if so designated by the Department of Energy. In the event that the Yucca Mountain site is chosen for development as the first repository, the conceptual design and subsequent preliminary engineering designs could be used to develop design specifications for repository construction. The design addresses the unique surface and subsurface characteristics of the volcanic tuffs at Yucca Mountain. A candidate horizon has been identified approximately 300 meters below the surface and about 100 meters above the water table. The concepts for the underground configuration have been developed to use underground regions which are defined by natural structural boundaries at the site. Thermal loadings within these regions have been selected (in the range of 12-15 w/m2) to satisfy performance constraints imposed to assure that the isolation provided by the site is not sign ificantly degraded. Studies are in progress to determine the preferred surface and underground configuration. Alternate waste emplacement concepts (horizontal or vertical) are being developed to optimize the ability to meet operational constraints, retrievability requirements, and cost objectives. 4 references, 4 figures, 3 tables